Blades used in tools such as electric grinders are utilized in a variety of applications where precise control of the tool may be required. Such applications include shaving mortar or concrete adhering to old bricks, tiles, concrete or frames and have the objective of removing such foreign matter from the substrate evenly and completely without damaging the substrate. As the grinder blade is engaged with the surface significant loading of the tool can result. The application of excessive force by the tool operator can result in overloading the tool, resulting in excessive current draw, overheating, excessive wear to tool components, or failure.
Such grinders generate significant amounts of dust and debris during operation. As a result of increasingly strict health and environmental regulations and concerns, the grinders often are provided with a safety cover or shield to contain or restrain the dust and debris, along with a vacuum device to collect the materials. Often the safety cover or shield has a mechanism, such as brushes, to provide a measure of a seal between the cover and the workpiece. The blade must be positioned appropriately with respect to the seal to allow appropriate contact with the workpiece to be made while brush contact is preserved.
The blades utilized in connection with the grinders and similar tools are interchangeable and replaceable. It is thus important that each blade when mounted on the tool is positioned properly with respect to the cover or shield to permit proper blade-workpiece contact to be maintained as blades are exchanged and replaced. As grinding is a force-intensive action, sufficient force must be applied to the tool to maintain appropriate contact between the rotating grinding wheel and the workpiece, but not excessive force that can stress or overload either the tool motor or grinding wheel.
It is accordingly the objective of the present invention to provide a coupling for the mounting of a grinder blade or similar rotating tool that can minimize or eliminate damage to the electrical tool due to repetitive and rapid changes in the load or heavy loads and which accommodates the necessary blade positioning for proper and efficient tool operation.